Wondering About 〜かす Verbs


#1

Hey everyone, lately I’ve noticed a few new verbs in my lessons with 〜かす in their 送り仮名 (乾かす,散らかす and 驚かす). Then I realized that I’ve also learned 欠かす,化かす,and 動かす!

Since they are all transitive verbs, I’m just curious if there is some common etymology there, similar to 〜やか, 〜なる and 〜らか 形容動詞 or 〜しい 形容詞.


#2

I do know that there’s a short form of the causative (From Wikipedia: A shortened causative form exists where the final -u becoming -asu for consonant stem verbs, and -ru becoming -sasu for vowel stem verbs), that would basically be the same thing.

動く’s normal causative is 動かせる, and the short form according to that rule would be, you guessed it, 動かす. So, in this case, maybe it just transitioned from being thought of as an intransitive in causative form, to just being thought of as a transitive verb in its own right.

I don’t know for sure though, that’s just piecing two things that make some sense to me together.

But in all honesty, StackExchange is the proper place to ask real questions about Japanese that might actually require knowledge or research. We don’t know jack here, comparatively.


#3

That makes a lot of sense. Thanks Leebo!